Cobham was top of the the pops today after hiking its dividend and receiving some positive comments from broker Jefferies, which said its full-year results appear 'robust and encouraging'. Basic pre-tax profit jumped 24% from £189m to £234m, while the underlying pre-tax profit rose 7% from £306m to £328m. The underlying trading margin improved to 19.7% from 18.3% in 2010. Meanwhile operating cash flow (after capital expenditure but before interest tax payments) rose from £271m to £337m.Well test results at Afren's Okoro East oil discovery, offshore Nigeria, have confirmed high quality oil in excellent reservoir sands, sending the group's shares soaring. Development, environmental and energy resources consultancy RPS Group rose after seeing full-year pre-tax profits come in marginally ahead of expectations. Meanwhile, TUI Travel, Renishaw and Kesa Electricals were all falling after trading without the right to their latest dividends. FTSE 250 - RisersCobham (COB) 209.70p +12.56%Cable & Wireless Worldwide (CW.) 33.24p +6.50%Inmarsat (ISAT) 458.10p +5.75%Afren (AFR) 132.00p +5.10%Michael Page International (MPI) 464.40p +4.83%Homeserve (HSV) 225.00p +4.80%Bodycote (BOY) 402.80p +4.54%Drax Group (DRX) 515.00p +4.02%Centamin (DI) (CEY) 82.10p +3.66%Spirit Pub Company (SPRT) 57.50p +3.60%FTSE 250 - FallersCable & Wireless Communications (CWC) 31.79p -3.52%TUI Travel (TT.) 187.60p -2.90%Dixons Retail (DXNS) 14.56p -2.87%New World Resources A Shares (NWR) 476.80p -2.34%COLT Group SA (COLT) 99.55p -1.92%Renishaw (RSW) 1,373.00p -1.86%Kesa Electricals (KESA) 70.00p -1.55%BlackRock World Mining Trust (BRWM) 698.50p -1.48%Wood Group (John) (WG.) 696.50p -1.28%Witan Inv Trust (WTAN) 481.30p -1.17%NR